"We are considering the option to attract other non-OPEC countries," he said, refusing to specify particular countries.

The agreement between OPEC and non-OPEC nations to slash crude oil production made in December 2016, expires in end-March 2018. The participants of the deal have committed to withdraw 1.8 million barrels per day from the oil market versus the level of October 2016. Currently, the issue whether to extend the agreement is the top priority of the OPEC+ agenda, and a decision is expected to be made at the November meeting in Vienna. The goal of the alliance is to reduce global oil reserves to an average level of five years, which will stabilize the oil price.